We present a risk-based approach for incorporating nonstationary probabilistic climate projections into long-term water resources planning. The proposed methodology uses nonstationary synthetic time series of future climates obtained via a stochastic weather generator based on the UK Climate Projections (UKCP09) to construct a probability distribution of the frequency of water shortages in the future. The UKCP09 projections extend well beyond the range of current hydrological variability, providing the basis for testing the robustness of water resources management plans to future climate-related uncertainties. The nonstationary nature of the projections combined with the stochastic simulation approach allows for extensive sampling of climatic variability conditioned on climate model outputs. The probability of exceeding planned frequencies of water shortages of varying severity (defined as Levels of Service for the water supply utility company) is used as a risk metric for water resources planning. Different sources of uncertainty, including demand-side uncertainties, are considered simultaneously and their impact on the risk metric is evaluated. Supply-side and demand-side management strategies can be compared based on how costeffective they are at reducing risks to acceptable levels. A case study based on a water supply system in London (UK) is presented to illustrate the methodology. Results indicate an increase in the probability of exceeding the planned Levels of Service across the planning horizon. Under a 1% per annum population growth scenario, the probability of exceeding the planned Levels of Service is as high as 0.5 by 2040. The case study also illustrates how a combination of supply and demand management options may be required to reduce the risk of water shortages.

Direct impedance measurement utilizing a medium previously described as being specific for Escherichia coli and which contains trimethylamine N-oxide (TMAO) and glucuronic acid was used to detect E. coli in water samples. The system was compared with the Colilert presence/absence test and the United Kingdom standard membrane filtration technique using membrane lauryl sulphate broth. The impedance method correlated well with both the traditional membrane method (93%) and the Colilert method (93.95%) for a number of different water types. No interference from Citrobacter spp. (as reported in previous studies) was detected in this study although some Salmonella spp. did give false-positive results. The data presented here suggest that the use of direct impedance may offer an alternative to conventional methods for the detection of E. coli in water.

The purpose of this study was to evaluate a methodology which could easily be used in any test laboratory in a uniform and consistent way for determining the sensitivity and reproducibility of results obtained with three ATP hygiene-monitoring systems. The test protocol discussed here allows such comparison to be made, thereby establishing a method of benchmarking both new systems and developments of existing systems. The sensitivity of the LUMINOMETER K, PocketSwab (Charm Sciences) was found to be between 0.4 and 4.0 nmol of ATP with poor reproducibility at the 40.0 nmol level (CV, 35%). The sensitivity of the IDEXX LIGHTING system and the Biotrace UNILITE Xcel were both between 0.04 and 0.4 nmol with coefficients of variation (CVs) of between 9% at 0.04 nmol and 10% at 0.4 nmol for the IDEXX system and 17% at 0.04 nmol and 21% at 0.4 nmol for the Biotrace system. The three systems were tested with a range of dilutions of different food residues: orange juice, raw milk, and ground beef slurry. All three test systems allowed detection of orange juice and raw milk at dilutions of 1:1,000, although the CV of results from the Charm system (54 and 74% respectively) was poor at this dilution for both residues. The sensitivity of the test systems was poorer for ground beef slurry than it was for orange juice and raw milk. Both the Biotrace and IDEXX systems were able to detect a 1:100 dilution of beef slurry (with CVs of 17 and 10% respectively), whilst at this dilution results from the Charm system had a CV of 55%. It was possible by using the method described in this paper to rank in order of sensitivity and reproducibility the three single-shot ATP hygiene-monitoring systems investigated, with the IDEXX LIGHTNING being the best, followed by the Biotrace UNILITE Xcel, and then the charm LUMINOMETER K, PocketSwab.

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In March 2000, a document entitled Draft Regional Planning Guidance for the South East was published with the primary aim of providing a regional framework for the preparation of development plans to the year 2016. This paper discusses the potential effects for the water industry of SERPLAN’s predicted levels of housing growth on water resources, sewage treatment and the environment. The need for sustainable development with the competing pressures of water‐resource limitation, changing regulation, increasing demand and the environment, are discussed. Thames Water’s scale of operations is described together with the range of measures aimed at managing the reasonable demands of customers, consistent with achieving sustainable growth. Basingstoke is described as a wastewater case study, highlighting the problem in fulfilling the sewerage undertaker’s statutory duties in (a) meeting already stringent effluent‐treatment standards which are necessary to maintain and improve river quality, and (b) providing the necessary infrastructure for an area which is earmarked for continuing development.